The increase in free erythrocyte porphyrins consequent to lead intoxication will be utilized as a mean to screen urban children for this insidious disorder. An extremely simple, rapid, reliable and inexpensive test (FEP test) has been developed in this laboratory. Preliminary results indicate that this test is eminently suitable to mass screening of large number of children by finger puncture. The test can be performed by collection of the sample on filter paper, which does not necessitate technically trained personnel. Thus the specimens could be mailed to a centralized laboratory. The proposed research will extend the application of this test to actual field investigation of populations of children at risk. These studies will also evaluate the use of samples collected on filter paper for diagnosis of anemia, hemoglobin abnormalities and other hematological disorders. The clinical significance of different parameters of lead intoxication will be evaluated by intensive study of suspected cases of lead intoxication. The temporal sequence of metabolic abnormalities and actual signs of intoxication will be studied in children with varying degrees of lead poisoning detected by these studies. These research promises to provide an extremely powerful tool for the detection and eradication of lead poisoning.